Everybody, meet Iceberg. Iceberg looks and behaves like a lot of other killer whales, with one very big exception: Iceberg is entirely white. In fact, researchers say he's the only all-white, adult orca to ever be observed.

A group of Russian scientists and students co-led by conservationist Erich Hoyt recently spotted Iceberg off the coast of Kamchatka in eastern Russia. Hoyt told BBC News:

We've seen another two white orcas in Russia but they've been young, whereas this is the first time we've seen a mature adult. It has the full two-metre-high dorsal fin of a mature male, which means it's at least 16 years old — in fact the fin is somewhat ragged, so it might be a bit older.

Iceberg seems to be fully socialised; we know that these fish-eating orcas stay with their mothers for life, and as far as we can see he's right behind his mother with presumably his brothers next to him.

Iceberg's age is significant. In the past, the only known all-white killer whales have been young — including an orca named Chima, who died in captivity.

Chima suffered from a rare genetic condition thought by many to be the underlying cause of her albinism, and while it's possible that Iceberg suffers from a similar condition, the fact that he's survived as long, and integrated into his pod, as well as he has suggests the source of his albinism may be something entirely different. Sate your appetite for Captain Ahab and Moby Dick jokes in the comments section below.